System fan management based on system loading options for a system having replaceable electronics modules

ABSTRACT

An electronic system has independently coolable first and second zones. The electronic system includes a first zone having a first zone fan and a plurality of first zone connectors for connecting electronic modules and a second zone having a second fan zone and a plurality of second zone connectors for connecting electronic modules. A module manager is also provided for communicating with the first and second zone connectors and with the first and second zone fans. The module manager can independently control the speed of the first and second zone fans based upon operational parameters received from the first and second zone connectors.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates generally to system fan management forcooling an electronic system and, more particularly, to automaticallymanaging cooling fan operation based upon the configuration ofreplaceable electronic modules within zones of such an electronicsystem.

2. Related Art

Advances in the miniaturization of computer, communication and otherelectronic equipment have led to the development of so-called “blade”systems, which permit several circuit boards (“blades”) to be installedin a single chassis. The chassis typically includes components, such aspower supplies, cooling fans, a blade manager, and other components thatare shared by all the blades installed in the chassis. The bladestypically plug into a backplane of the chassis, which distributes powerand data signals between the blades, blade manager, and othercomponents. This arrangement enables a large number of blades to behoused in a relatively small chassis. Oftentimes, the chassis isdimensioned to be mounted in a rack, such as a server rack with otherrack-mounted equipment.

Blades are typically designed to be “hot swappable”, that is, they canbe installed into or removed from a chassis without removing power fromall components in the chassis. This enables an operator or systemmanager to replace a failed or failing blade with a replacement bladewithout adversely affecting real-time operations of other chassiscomponents. In addition, spare blades can be installed in a chassis,without activating them, to serve as “standby” blades.

Blades can perform various functions. Most blades contain entirecomputers, including single or multiple processors, memory, and networkinterfaces. Most computer blades are used as servers while others areused as communication devices, such as routers, firewalls or switches.Some blades contain specialized hardware components, in addition to orinstead of processors, memory, etc. Typically, any type of blade can beplugged into any slot of a chassis. This enables an operator or systemmanager to “mix and match” blades in a chassis so that requisiteoperations can be performed by the blade system. In addition, themixture of blade types can be changed to accommodate changes inoperational requirements.

Some server blades include disk drives. Other blades access disk drivesthat are located elsewhere in the chassis or are connected to thechassis by computer network hardware. The blade manager establisheslogical network connections between these blades and off-blade diskdrives. Since these blades can be connected to different disk drivescontaining different software at different times, these blades canexecute different operating systems and/or application programs, and canaccess different data at different times. For example, a system operatormight choose to logically connect a blade to different disk drives toexecute different application programs at different times of a day. Inanother example, if a blade fails, logical connections from off-bladedisk drives that were formerly used by the failed blade can beredirected to a replacement or hot standby blade.

Some blades can be field-upgraded, such as by installing additionalmemory, processors or other components on the blades. In contrast, somemanufacturers prefer to produce blades that are fully populated withsuch additional hardware. These manufacturers selectively enable ordisable the additional hardware when the blades are manufactured, totailor the blade capabilities to the customers' initial needs andbudgets. Later, if a customer purchases a license to upgrade a blade,all or a portion of the additional hardware can be enabled withoutreconfiguring (which requires removal of the blade from the chassis) orreplacing the blade.

Though blade servers provide many advantages, several engineeringchallenges arise when using bladed servers. Among these challenges isthe challenge of designing and operating a bladed system such that theheat generated by the blades is sufficiently removed in the limitedspace available in the chassis that hosts the system. Some known powerlimiting strategies include powering down a CPU functional unit, e.g., afloating point unit or an on-die cache, or trading off speed for reducedpower consumption in a hard drive. To address heat dissipationchallenges, bladed server systems can be designed with an underlyingpower and thermal envelope. For example, when a chassis that hosts abladed system has a limited amount of airflow available to cool theblades (i.e., when the system can only dissipate a limited amount ofheat), then the chassis is designed for a limited amount of powerconsumption and an associated limited performance of the blades.

As a result of the modularity and flexibility of such bladed systemshowever, different portions of a chassis that holds the blades maycontain more or fewer blades, blades that run hotter than other blades,blades with processors that run at different clock frequencies thanprocessors on other blades, and/or blades that have been turned on orturned off during operation of the bladed system. As a result, thecooling needs within a particular chassis can vary from time to time,and, in particular, the cooling needs of more than one cooling regionwithin the blade chassis (each cooling region served by one or moreseparate cooling fans) can vary from time to time. In order to optimizethe usage of available power in a bladed system, previous systems havechanged the speed of all of the fans in a chassis together, withoutregard to the location of individual fans in the chassis, based onsystem parameters such as temperature within the chassis.

SUMMARY OF THE INVENTION

In one aspect of the invention, an electronic system havingindependently coolable first and second zones is provided. Theelectronic system includes a first zone having a first zone fan and aplurality of first zone connectors for connecting electronic modules anda second zone having a second fan zone and a plurality of second zoneconnectors for connecting electronic modules. A module manager is alsoprovided for communicating with the first and second zone connectors andwith the first and second zone fans. The module manager canindependently control the speed of the first and second zone fans basedupon operational parameters received from the first and second zoneconnectors.

In a further aspect of the invention, a method for cooling an electronicsystem is provided. The electronic system has a module manager and aplurality of replaceable electronic modules provided in a plurality ofzones with each zone having an independently controllable cooling fan.In the method, the module manager receives one or more operationalparameters from the first zone of the electronic system, and one or moreoperational parameters from a second zone of the electronic system. Themodule manager then calculates a desired speed for a cooling fanassociated with the first zone of the electronic system and provides acontrol signal indicating the desired speed to the cooling fanassociated with the first zone. The module manager further calculates adesired speed for a cooling fan associated with the second zone of theelectronic system and provides a control signal indicating the desiredspeed to the cooling fan associated with the second zone.

In a still further aspect of the invention, a module manager forindependently controlling a first zone fan for cooling a first zone ofan electronic system and a second zone fan for cooling a second zone ofthe electronic system is provided where the electronic system has aplurality of replaceable electronic modules. The module manager includesa first receiver configured to receive one or more operationalparameters from the first zone of the electronic system and a secondreceiver configured to receive one or more operational parameters fromthe second zone of the electronic system. The module manager alsoincludes a calculator configured to calculate a first control signal forcontrolling the first zone fan based on the one or more operationalparameters received from the first zone of the electronic system and asecond control signal for controlling the second zone fan based on theone or more operational parameters received from the second zone of theelectronic system. The module manager further includes a communicatorconfigured to communicate the first and second control signals to thefirst and second fans, respectively.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of an electronic system of the invention;

FIG. 2 is a perspective view of an exemplary blade system, in whichaspects of the present invention can be implemented; and

FIG. 3 is a schematic block diagram of the blade system of FIG. 2illustrating components of the blade system, in accordance with oneembodiment of the present invention.

DETAILED DESCRIPTION

The present invention provides methods and systems to automaticallymanage cooling fan operating conditions in different zones within anelectronic system based upon the configuration of replaceable electronicmodules within the electronic system. The electronic system includes anumber of connectors for connecting replaceable electronic modules in atleast two zones with each zone having a separate cooling fan. Anelectronic module manager (hereinafter “module manager”) communicateswith the connectors to determine whether any electronic modules areconnected, and if electronic modules are connected, to optionallydetermine operating parameters of the electronic modules that relate tothe modules' cooling requirements. The module manager then controls thespeed of each cooling fan independently according to the coolingrequirements of the electronic modules present in a particular zone.

Replaceable electronic modules include blades; circuit boards thatconnect to other circuits by plugs, sockets, soldered wire connectionsor any other conventional electrical connection; “daughter” boards;integrated circuits; monitors; and any electronic component, circuit orsubsystem (hereinafter, electronic module) that can be connected toother modules, as long as the modules can be initially connected to theother modules or they can be disconnected from their respective modulesand the same or replacement modules can be connected in their places.For purposes of providing an example, the present invention will bedescribed in the context of a blade system. As noted, a blade system isa printed circuit board (called the backplane or midplane), which isinstalled in a chassis along with a plurality of other printed circuitboards, or blades, that plug into it. In such a system, blades can failand be replaced by replacement blades. The failed blades can be left in,or removed from, the blade system. In addition, blades can be replacedfor reasons other than blade failure, such as to facilitate bladetesting. One of ordinary skill in the art can, however, apply theteachings herein to other types of modules, including but not limited tothose listed above.

FIG. 1 illustrates an exemplary electronic system 100 of the inventionhaving a chassis frame 120 holding at least one chassis 122 for furtherholding replaceable electronic modules in at least two zones: a firstzone 124 and a second zone 126. In order to view other details ofchassis frame 120, replaceable electronic modules have not beenillustrated in FIG. 1, but rather first zone 124 (the left zone) hasbeen labeled as having blades connected to first zone connectors 132 andsecond zone 126 (the right zone) has been labeled as having no bladesconnected to second zone connectors 134. FIG. 2 provides an illustrationof a chassis 122 in which blades 104 are illustrated and, as labeled inFIG. 1, blades 104 are provided in first zone 124, while no blades areprovided in second zone 126.

Electronic system 100 of FIG. 1 further includes a first zone fan 128,which creates a first zone air flow 136, and a second zone fan 130,which creates a second zone air flow 138, with both fans pulling airfrom a cooling air input flow 140. First zone air flow 136 isillustrated as being significantly larger than second zone airflow 138to show that first zone fan 128 and second fan 130 have beenindependently controlled to provide a larger air flow through first zone124 due to the fact that more blades are present in the first zone thanin second zone 126.

In the illustrated configuration, first and second power supplies 142,148 are provided with first and second power supply fans 144, 150 whichdraw air from first zone 124 and second zone 126, respectively, throughpower supplies 142, 148 to create first and second power supply outputair flows 146, 152. As illustrated, first power supply output air flow146 is larger than second power supply output air flow 152 by an amountthat is proportional to the amount by which first zone air flow 136 islarger than second zone air flow 138. In this case, the speeds of secondzone fan 130 and second power supply fan 150 have been controlled incoordination to have a lower speed with respect to first zone fan 128and first power supply fan 148 based on the fact that there are noblades loaded in second zone 126. The result of this fan control is azone-based optimization of power and thermal envelope usage by reducingfan speeds in a zone that requires less cooling.

Further details of chassis 132 and blades 104 are illustrated in thediagram of FIG. 2 as well as the functional block diagram of FIG. 3. Forexample, blades 104 a-d slide into chassis 120 and plug into a backplane(not visible in FIG. 2, but illustrated functionally in FIG. 3 with thephysical connections made through first and second zone connectors 132,134 illustrated in FIG. 1). In the illustrated embodiment, a blademanager 106 also slides into chassis 120 and plugs into the backplane(here, the blade manager is one of the blades 104, in particular blade104 d). Blade manager 106 need not be removable, and for purposes of thepresent invention, need not be located in chassis 120. In addition,blade manager 106 can be connected to, and can control blades in, otherchassis over a suitable network link. Each blade 104 a-d containsappropriate components 108, 110 and 112, such as processors, memory,network interfaces, disk drives, etc., depending on the blade's intendedfunction. Optionally, each blade 104 a-d can include a connector 114, bywhich a keyboard, video monitor, and mouse (collectively, “KVM”) can beconnected to the blade to provide a user interface therewith. Similarly,blade manager 106 can include an optional KVM connector 116 to provide auser interface with the blade manager.

As further illustrated in the architectural block diagram of FIG. 3,backplane 202 interconnects components of blade system as blades 104a-d, optionally including blade manager 106, plug into backplane 202.Blade manager 106 communicates over backplane 202 with blade controlcircuits 208 a-d on each of the blades 104 a-d, respectively. Thiscommunication is preferably carried over a dedicated set of signal linesin backplane 202. Alternatively, this communication can be over shareddata lines in backplane 202 or over a signal path separate from thebackplane. For example, a separate wired or wireless Ethernet connectioncan be used. Blade control circuits 208 a-208 c control availability ofpower, operation state of processor(s), and other aspects of the blades104 a-d, as is well known in the art. As one example of such control,reference is made to U.S. patent application Ser. No. 10/216,285;entitled “System and Method for Managing the Operating Frequency ofProcessors or Blades” (also identified as Attorney Docket No.100202881-1) and filed in August of 2002, which application is herebyincorporated by reference for its teaching of operating frequencymonitoring and control in a bladed architecture, as well as the furtherUnited States Patent Applications listed as related and incorporated byreference into that application relating to further monitoring andcontrol in a bladed architecture. Blade manager 106 can thus receive avariety of operational parameters relating to the activity of electronicmodules such as blades 104 located in first 124 and second 126 zones ofelectronic system 100, including, but not limited to, the number ofelectronic modules connected within a zone, the number of electronicmodules that are operating within the zone, the operational frequency ofany electronic modules connected within the zone, the voltage of anyelectronic modules connected within the zone, and the power consumed byany electronic modules connected within the zone, the temperature of theelectronic module or of a particular processor or other component, andcombinations of these operating parameters. These parameters can bereceived dynamically or periodically.

Each blade 104 a-d includes an EE-PROM 210 a-d, respectively, or othertype of persistent memory to store configuration information for theblade. Any type of persistent memory that retains its contents withoutthe availability of power can be used. The configuration information caninclude, for example, serial number and license information, as well asother blade identification or configuration information. The followingdiscussion is presented in the context of blade 104 a. Unless otherwisenoted, the following description applies to any blade 104 a-d.

Blade manager 106 also includes an EE-PROM 212 or other type ofpersistent memory. The blade manager's persistent memory need not beco-located with blade manager 106, as long as the persistent memory isaccessible to blade manager. For example, the persistent memory can be adisk drive and/or it can be located elsewhere in chassis 122.Alternatively, the blade manager's persistent memory can be made up ofseveral parts, each in a different location. Alternatively, blademanagers 222 of several blade systems 100 can share a common persistentmemory that is suitably connected to the blade managers. In thefollowing discussion, persistent memory 212 will be referred to hereinas EE-PROM 212 for simplicity, but the discussion applies to any form ofpersistent memory.

As noted, a user interface 214 can be connected to blade manager 106 viathe connector 116. Alternatively, a remote user interface 216 can beconnected to blade manager 106 via a network link or other suitableconnection 218. In the following discussion, reference to user interface214 also applies to user interface 216. Optionally, a user interface 220can connect to blade 104 a via connector 114. Alternatively, userinterface 214 or 216 can communicate with blade 104 a. In this case,blade manager 106 relays commands and responses to and from blade 104 aover backplane 202.

As discussed above, blade manager 106 need not be located within bladesystem 100. For example, remote blade manager 222 can communicate withblade system 100 over a communication link 224. Such a communicationlink 224 can be provided by, for example, a wire or wireless local areanetwork (LAN). As with blade manager 106, remote blade manager 222includes an EE-PROM or other suitable persistent memory 226 and can havea directly-connected or remote user interface (not shown), similar tothe user interfaces 214 and 216. As discussed above, blade manager 106can communicate with and control blades in another chassis via acommunication link 224. The following discussion refers to blade manager106. However, unless otherwise noted, the following discussion alsoapplies to remote blade manager 222.

Disk drives, such as local disk drive 228 or remote disk drive 230, canbe connected to backplane 202. Remote disk drive 230 can be connected tobackplane 202 via a suitable network connection 232, as is well know inthe art.

In addition, first and second zone fans 128, 130 can receive independentcontrol signals 242, 244 from blade manager 106 through backplane 202 orby another connection known in the art. Control signals 242, 244 arecalculated (for example by using a policy management system havingpolicies regarding fan operation) by blade manager 106 based upon thepresence and optionally the operating characteristics of any blades 104present in a particular zone. In one embodiment, the speed of first andsecond zone fans 128, 130 is established using pulse width modulation asis known in the art, and control signals 242, 244 are indicative of thepulse width to be employed and thus the speed of the fans in theseparate zones. First and second power supply fans 144, 150 can beindependently controlled by blade manager 106 in much the same way asfirst and second zone fans 128, 130 are, or they can share a controlsignal with the first and second zone fans—for example, control signal242 could be shared by first zone fan 128 and first power supply fan 144and control signal 244 could be shared by second zone fan 130 and secondpower supply fan 150.

The invention may also be embodied in a method for cooling an electronicsystem having a module manager and a plurality of replaceable electronicmodules provided in a plurality of zones with each zone having anindependently controllable cooling fan. In this embodiment, the modulemanager receives one or more operational parameters from each of a firstand second zone of the electronic system. The module manager thencalculates a desired speed for a first zone cooling fan and provides acontrol signal indicating the desired speed to the first zone coolingfan associated with the first zone, and calculates a desired speed forthe second zone cooling fan and provides a control signal indicating thedesired speed to the second zone cooling fan associated with the secondzone. In this embodiment, each of the other features of the inventiondescribed above may be employed.

Embodiments have been described in which the present invention isemployed in a blade system to automatically or dynamically managecooling fans in different zones. However, one of ordinary skill in theart can apply the teachings herein to systems having other types ofelectronic modules. For example, rack mounted servers or other rackmounted electronic components can have fans in different zones. Suchrack mounted components often include control circuitry on eachcomponent that monitors and controls local operating conditions,typically in communication with a dedicated controller or workstationrunning monitoring and control software such as that available fromHewlett-Packard Co. under the name OpenView. Such a system could readilybe adapted to utilize the present invention.

The terms and expressions employed herein are used as terms ofdescription, not of limitation. There is no intention, in using theseterms and expressions, to exclude any equivalents of the features shownor described or portions thereof. Practitioners in the art willrecognize that other modifications are possible within the scope of theinvention claimed.

1-17. (canceled)
 18. A method for cooling an electronic system having amodule manager and a plurality of replaceable electronic modulesprovided in a plurality of zones with each zone having an independentlycontrollable cooling fan, comprising: receiving by the module managerone or more operational parameters from a first zone of the electronicsystem, wherein the received operational parameters comprise a voltageof any electronic modules connected within the first zone; receiving bythe module manager one or more operational parameters from a second zoneof the electronic system, wherein the received operational parameterscomprise a voltage of any electronic modules connected within the secondzone; calculating by the module manager a desired speed for a coolingfan associated with the first zone of the electronic system based on thereceived voltage(s) of the electronic module(s) connected within thefirst zone, and providing a control signal indicating the desired speedto the cooling fan associated with the first zone; and calculating bythe module manager a desired speed for a cooling fan associated with thesecond zone of the electronic system based on the received voltage(s) ofthe electronic module(s) connected within the second zone, and providinga control signal indicating the desired speed to the cooling fanassociated with the second zone.
 19. The method of claim 18, wherein thecalculated speed of the first zone fan is different than the calculatedspeed of the second zone fan.
 20. The method of claim 18, wherein thefirst zone further has a second first zone fan and the second zonefurther has a second second zone fan.
 21. The method of claim 20,wherein the second first zone fan and the second second zone fan areeach associated with a dedicated power supply module.
 22. The method ofclaim 21, wherein the power supply module associated with the secondfirst zone fan provides power to any electronic modules connected withinthe first zone and the power supply module associated with the secondzone fan provides power to any electronic modules connected in thesecond zone.
 23. The method of claim 20, wherein the first zone fanspeed and the second first zone fan speed is coordinated to result in adesired cooling of any electronic modules connected in the first zone.24. The method of claim 23, wherein the first zone fan and the secondfirst zone fan share a common control signal.
 25. The method of claim18, wherein the operational parameters received by the module managerfor a given zone also include the number of replaceable electronicmodules connected within the respective first and second zones.
 26. Themethod of claim 18, wherein the operational parameters received by themodule manager for a given zone also include the number of replaceableelectronic modules that are operating within the respective first andsecond zones.
 27. The method of claim 18, wherein the operationalparameters received by the module manager for a given zone include alsothe operational frequency of any replaceable electronic modulesconnected within the respective first and second zones.
 28. (canceled)29. The method of claim 18, wherein the operational parameters receivedby the module manager for a given zone also include the power consumedby any replaceable electronic modules connected within the respectivefirst and second zones.
 30. The method of claim 18, wherein the firstand second zones are located within a chassis.
 31. The method of claim30, wherein the chassis includes a backplane having the first and secondzone connectors.
 32. The method of claim 31, wherein the chassis isprovided within a rack which carries the first and second zone fans andat least one power supply module.
 33. The method of claim 18, whereinthe electronic system employs a bladed architecture.
 34. The method ofclaim 18 further comprising the module manager receiving updatedoperational parameters and adjusting the speed of the first and secondzone fans.
 35. (canceled)
 36. A method for cooling an electronic systemhaving a module manager and a plurality of replaceable electronicmodules provided in a plurality of zones with each zone having anindependently controllable cooling fan, comprising: receiving by themodule manager one or more operational parameters from a first zone ofthe electronic system, wherein the received operational parameterscomprise the number of any electronic modules connected within the firstzone; receiving by the module manager one or more operational parametersfrom a second zone of the electronic system, wherein the receivedoperational parameters comprise the number of any electronic modulesconnected within the second zone; calculating by the module manager adesired speed for a cooling fan associated with the first zone of theelectronic system based on the received number of electronic module(s)connected within the first zone, and providing a control signalindicating the desired speed to the cooling fan associated with thefirst zone; and calculating by the module manager a desired speed for acooling fan associated with the second zone of the electronic systembased on the received number of electronic module(s) connected withinthe second zone, and providing a control signal indicating the desiredspeed to the cooling fan associated with the second zone.
 37. A methodfor cooling an electronic system having a module manager and a pluralityof replaceable electronic modules provided in a plurality of zones witheach zone having an independently controllable cooling fan, comprising:receiving by the module manager one or more operational parameters froma first zone of the electronic system, wherein the received operationalparameters comprise the number of any electronic modules operatingwithin the first zone; receiving by the module manager one or moreoperational parameters from a second zone of the electronic system,wherein the received operational parameters comprise the number of anyelectronic modules operating within the second zone; calculating by themodule manager a desired speed for a cooling fan associated with thefirst zone of the electronic system based on the received number ofelectronic module(s) operating within the first zone, and providing acontrol signal indicating the desired speed to the cooling fanassociated with the first zone; and calculating by the module manager adesired speed for a cooling fan associated with the second zone of theelectronic system based on the received number of electronic module(s)operating within the second zone, and providing a control signalindicating the desired speed to the cooling fan associated with thesecond zone.
 38. A method for cooling an electronic system having amodule manager and a plurality of replaceable electronic modulesprovided in a plurality of zones with each zone having an independentlycontrollable cooling fan, comprising: receiving by the module managerone or more operational parameters from a first zone of the electronicsystem, wherein the received operational parameters comprise anoperational frequency of one or more electronic modules connected withinthe first zone; receiving by the module manager one or more operationalparameters from a second zone of the electronic system, wherein thereceived operational parameters comprise an operational frequency of oneor more electronic modules connected within the second zone; calculatingby the module manager a desired speed for a cooling fan associated withthe first zone of the electronic system based on the receivedoperational frequency of electronic module(s) connected within the firstzone, and providing a control signal indicating the desired speed to thecooling fan associated with the first zone; and calculating by themodule manager a desired speed for a cooling fan associated with thesecond zone of the electronic system based on the received operationalfrequency of electronic module(s) connected within the second zone, andproviding a control signal indicating the desired speed to the coolingfan associated with the second zone.
 39. A method for cooling a bladedarchitecture system having a blade manager and a plurality ofreplaceable blades connected within a plurality of zones of a chassisand wherein each zone has an independently controllable cooling fan,comprising: receiving by the blade manager one or more operationalparameters from a first zone of the electronic system; receiving by theblade manager one or more operational parameters from a second zone ofthe electronic system; calculating by the blade manager a desired speedfor a cooling fan associated with the first zone of the electronicsystem based on the received operational parameters for the first zone,and providing a control signal indicating the desired speed to thecooling fan associated with the first zone; calculating by the blademanager a desired speed for a cooling fan associated with the secondzone of the electronic system based on the received operationalparameters for the second zone, and providing a control signalindicating the desired speed to the cooling fan associated with thesecond zone; managing by the blade manager one or more of the bladesconnected within the plurality of zones; and establishing by the blademanager one or more logical connections between the blades.
 40. Themethod of claim 39, wherein the blade manager is embodied on a bladeconnected within one of the plurality of zones.
 41. The method of claim39, wherein the blade manager is embodied o a blade located outside thechassis.
 42. The method of claim 39, further comprising: managing by theblade manager one or more blades located in a separate chassis.
 43. Themethod of claim 39, wherein the operational parameters received by theblade manager for a give zone include the number of blades that areconnected within the given zone.
 44. The method of claim 39, wherein theoperational parameters received by the blade manager for a given zoneinclude the number of blades that are operating within the given zone.45. The method of claim 39, wherein the operational parameters receivedby the blade manager for a given zone include the operational frequencyof one or more blades connected within the given zone.
 46. The method ofclaim 39, wherein the operational parameters received by the blademanager for a given zone include the voltage of any blades connectedwithin the given zone.
 47. The method of claim 39, wherein theoperational parameters received by the blade manager for a given zoneinclude one or more of the power consumed by any blades connected withinthe given zone, and the thermal envelope associated with each slot inthe chassis and/or each individual blade that plugs into the chassis.